Posted
by
samzenpus
on Thursday April 14, 2011 @04:21AM
from the three-shells-clean dept.

RedEaredSlider writes "Crab shells may soon be used to take radioactive contaminants out of water. Joel Pawlak, an associate professor of forest biomaterials at North Carolina State University, has developed a material similar to foam rubber that absorbs water and attaches to molecules dissolved in it, leaving pure and potable water behind. The material is a combination of hemicellulose and chitosan. The first comes from wood and is extracted by the ton in the paper-making process. Chitosan is extracted from ordinary crustacean shells — primarily crab, shrimp and lobster — by treatment with hydrochloric acid and then sodium hydroxide."

If it works for radioactivity, could it work for almost anything? I mean could you literally put blood in one end and get clean water out the other? Not sure where I'm going with this but intersting...

You could put (say) blood in at one end and get potable water out at the other end, along with a plugged and useless filter and a significant quantity of "blood concentrate". This is generally true for all filtering systems, and the more effective the filter, the faster it happens.

SOME (not all) filtering systems can be reverse-flushed to regenerate them, but for that, you need a supply of potable water to do the flushing with (otherwise you'fe got a filter contaminated on both sides.

So we're going to take parts of wildlife apart to clean the environment we destroyed to save the wildlife? Interesting...
I'm a little curious how they'll COLLECT the shells. Are we going to buy the byproducts of a factory that produces frozen pre-made seafood?

Probably. Just look at how many crabs are eaten. Now look at how many of those sold have a shell still attached. It's turning waste from two different sources into a usable solution to a major problem - and one that's just become even more significant.

I don't think that because glucosamine as a dietary supplement is pretty expensive, it follows that that glucosamine as an industrial reagent will be as well. The prices of medicines and supplements rarely are cost of production and distribution plus reasonable markup.

Sounds like they're combining the properties of both a cationic and anionic polymer with the idea of maximizing the surface area on which the adhesion occurs (similar to activated carbon).

Basically, in layman's terms... most things that dissolve in water form ions (either positively or negatively charged), which can be removed by their electrostatic adhesion to oppositely-charged ions. According to TFA, this polymer foam has both positively and negatively charged ions at its surface for the dissolved ions to adhere to (perhaps someone with more knowledge of organic chemistry could tell me if this is fairly unique? I've never heard of a polymer which was both cationic and anionic). Since the ions actually cling to its surface, the surface area should be maximized (the principle behind an activated carbon filter), which in this case they're doing by making it into a foam.

What they didn't tell you is that it will birth Lobersteron the Terrible! Sucking all that radiation into its carapace he will grow to the size of a large skyscraper and terrorize the countryside. Fortunately he will probably cross paths with Crabucon the Munificent and will duke it out, the loser slinking back into the ocean. Of course the urban devastation will be horrible, but whatcha gonna do... Hopefully it will be DJ'ed by the Beastie Boys.

There is no difference in removing radioactive materials from seawater than removing non-radioactive materials. Each atom of I-131 is exactly Iodine until that moment when it decides to decay and transform into Xenon-131, a stable isotope. This method may be useful only if it can remove contaminants at very low mass concentrations. The total amount of I-131 released at Fukushima is only around 100 grams, assuming the values in the news are correct. The reported concentration at one of the outfalls, at sever

I recently shifted from ordinary disposable filters (that cost an arm and a leg per year for the average family here in Europe) to a swiss-made ceramic-based one that can be cleaned after a while, and is expected to last years (I indeed used it for one year now without wear).I understand this method is more for bacterias etc. rather than ions, so maybe the crab-related thingie could be set just after;-)For this now I also have a carbon flter that removes some ions (chlore among others) but certainly not ra

The principle here is not actual filtration (such as is done by your ceramic filters). It is actually the electrostatic attraction between charged ions. Rather than a lattice structure in which large impurities get "stuck", this is a surface to which impurities adhere. It's like fly-paper, or those cat-hair removers.

Making it into a foam is not designed to trap the impurities, but rather to give the impurities a lot of surface area to stick to. The impurities don't get stuck because they can't find any open

Since this relies on chemical properties of dissolved radioactive elements, it shouldn't have any effect on deuterium and tritium bound up in water molecules. Deuterium isn't actually radioactive, but tritium is, so there could still be some radioactivity. I don't know how much tritiated water is likely to be contained in conatminated water, though (it might vary depending on the source), so it might not actually be that much of a problem.